JP2021081383A - Magnetic characteristic measuring device and magnetic characteristic measuring method - Google Patents

Abstract

To appropriately evaluate magnetic characteristics even when core intervals of electric magnets are different.SOLUTION: A magnetic characteristic measuring device 1 comprises: a pair of electric magnets 11, with a search coil 21 wound around, which are arranged so as to sandwich a magnetic material 2; a hall sensor 22 for measuring a magnetic field strength H; and a control device 30 for measuring the magnetic characteristic of the magnetic material 2 by the magnetic field strength H and a magnetic flux density B while supplying an excitation current to the pair of electric magnets 11. The control device 30 includes a storage unit 34 for storing a relationship, as electric magnet characteristic information, between the excitation current acquired in advance for each clearance G of the pair of electric magnets 11 and the magnetic field strength H, an input unit 31 to which is inputted the amplitude and cycle of an excitation magnetic field, and a measurement control unit 33 for executing measurement control. The measurement control unit 33 acquires a target current value on the basis of the electric magnet characteristic information and sets the current waveform of the excitation current on the basis of the cycle of the excitation magnetic field and the target current value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a magnetic characteristic measuring device and a magnetic characteristic measuring method.

The BH characteristics of a magnetic material can be evaluated by measuring the magnetic flux density with respect to the strength of the applied magnetic field, and the magnetism such as coercive force, residual magnetic flux density, magnetic permeability, and hysteresis loss can be evaluated from the so-called magnetic hysteresis loop. The characteristics can be obtained. Here, in general, in the measurement of BH characteristics, a ring-shaped test piece in which an exciting coil is wound is used for a soft material (soft magnetic material), and a hard material (hard magnetic material). When a wider range of exciting magnetic fields is required, an electromagnet provided so as to sandwich the magnetic material to be measured is used. For example, Patent Document 1 has a magnetic hysteresis characteristic device that has two cores that face each other and are arranged so as to sandwich a magnetic material, and magnetizes the magnetic material by energizing a solenoid wound around the core. Is disclosed.

The above-mentioned electromagnet used for measuring the BH characteristics is configured so that the distance between the pair of cores can be adjusted according to the size of the magnetic material, whereby the magnetic material can be magnetized efficiently. it can. Further, in the above-mentioned prior art according to Patent Document 1, the strength of the magnetic field generated by the electromagnet with respect to the magnetic material is detected by the Hall element.

Jikkai Sho 63-67886

However, in the above-mentioned conventional technique, the strength of the magnetic field generated by the electromagnet differs depending on the distance between the two cores. Therefore, for example, when measuring the BH characteristics of a plurality of magnetic materials having different dimensions, the desired strength is obtained. The target current value to be energized in the solenoid to apply the magnetic field of is also different. Therefore, the time required to raise the current value flowing through the solenoid from 0 [A] to the target current value, that is, the time required to reach the desired magnetic field strength also changes depending on the core spacing of the electromagnet. At this time, the width of the magnetic hysteresis loop becomes narrower as the period of the applied magnetic field becomes longer, and becomes thicker as the period of the applied magnetic field becomes shorter. That is, since a plurality of magnetic materials having different dimensions have different periods of magnetic fields applied according to the core spacing of the electromagnet, the measured BH characteristics are different from each other even if they are made of the same material. Therefore, there is a risk that the magnetic characteristics cannot be properly evaluated.

The present invention has been made in view of such a situation, and an object of the present invention is to measure magnetic characteristics so that appropriate evaluation of magnetic characteristics can be performed even when the core spacing of electromagnets is different. It is an object of the present invention to provide an apparatus and a method for measuring magnetic characteristics.

<First aspect of the present invention>
The first aspect of the present invention is a pair of electromagnets in which a search coil is wound and arranged so as to sandwich a magnetic material, a magnetic field sensor for measuring the magnetic field strength between the pair of electromagnets, and the pair of electromagnets. The control device comprises a control device that measures the magnetic characteristics of the magnetic material by the magnetic field strength measured by the magnetic field sensor and the magnetic flux density measured by the search coil while supplying an exciting current to the magnetic material. , A storage unit that stores the relationship between the exciting current and the magnetic field strength acquired in advance for each separation interval of the pair of electromagnets as electromagnet characteristic information, and the amplitude and period of the exciting magnetic field that excites the magnetic material are input. The measurement control unit includes an input unit and a measurement control unit that executes measurement control of the magnetic characteristics, and the measurement control unit includes a target current corresponding to the separation interval and the amplitude of the exciting magnetic field based on the electromagnet characteristic information. This is a magnetic characteristic measuring device that acquires a value and sets a current waveform of the exciting current based on the period of the exciting magnetic field input from the input unit and the target current value.

In the magnetic characteristic measuring apparatus according to the first aspect of the present invention, the relationship between the exciting current and the magnetic field strength for each separation interval of a pair of electromagnets is stored in advance, and the exciting magnetic field for exciting the magnetic material to be measured is excited. By inputting the amplitude and period of, the current waveform of the exciting current applied to the pair of electromagnets is set. At this time, the current waveform of the exciting current has an amplitude necessary for applying a predetermined target magnetic field to the magnetic material regardless of the size of the separation interval, and the period can be arbitrarily set. Therefore, for example, even when two magnetic materials made of the same material and having different dimensions are measured, the magnetic characteristics can be evaluated under the same conditions by unifying the period of the exciting current. Therefore, according to the magnetic characteristic measuring apparatus according to the present invention, it is possible to appropriately evaluate the magnetic characteristic even when the core spacing of the electromagnet is different.

<Second aspect of the present invention>
In the second aspect of the present invention, in the first aspect of the present invention described above, the measurement control unit supplies a attenuated alternating current to the pair of electromagnets before measuring the magnetic characteristics, and the pair of electromagnets. It is a magnetic property measuring device that demagnetizes an electromagnet.

According to the magnetic characteristic measuring apparatus according to the second aspect of the present invention, the residual magnetic flux density of the core in the pair of electromagnets is demagnetized by supplying a attenuated alternating current to the pair of electromagnets before the measuring step. It is possible to reduce the influence of the above, and in particular, it is possible to improve the reliability of the measurement result for the soft material (soft magnetic material) and the semi-hard material (semi-hard magnetic material).

<Third aspect of the present invention>
A third aspect of the present invention includes an arrangement step of arranging a magnetic material around which a search coil is wound so as to be sandwiched between a pair of electromagnets, a set value of an amplitude and a period of an exciting magnetic field for exciting the magnetic material, and the above. A set value acquisition step for acquiring the separation interval of the pair of electromagnets, a current waveform setting step for setting the current waveform of the exciting current supplied to the pair of electromagnets, and a step of setting the current waveform when the pair of electromagnets are excited by the current waveform. In the measurement step of acquiring the magnetic field strength between the two and the magnetic flux density measured by the search coil to measure the magnetic characteristics of the magnetic material, and in the current waveform setting step, every distance between the pair of electromagnets is included. Based on the electromagnet characteristic information as the relationship between the exciting current and the magnetic field strength acquired in advance, a target current value corresponding to the separation interval and the amplitude of the exciting magnetic field is acquired, and the period of the exciting magnetic field is obtained. This is a method for measuring magnetic characteristics, in which the current waveform is set from the target current value.

In the magnetic characteristic measuring method according to the third aspect of the present invention, the relationship between the exciting current and the magnetic field strength for each separation interval of a pair of electromagnets is stored in advance, and the exciting magnetic field for exciting the magnetic material to be measured is used. By inputting the amplitude and period of, the current waveform of the exciting current applied to the pair of electromagnets is set. At this time, the current waveform of the exciting current has an amplitude necessary for applying a predetermined target magnetic field to the magnetic material regardless of the size of the separation interval, and the period can be arbitrarily set. Therefore, for example, even when two magnetic materials made of the same material and having different dimensions are measured, the magnetic characteristics can be evaluated under the same conditions by unifying the period of the exciting current. Therefore, according to the magnetic characteristics measuring method according to the present invention, it is possible to appropriately evaluate the magnetic characteristics even when the core spacing of the electromagnets is different.

<Fourth aspect of the present invention>
A fourth aspect of the present invention is, in the third aspect of the present invention described above, a magnetic property in which a decaying alternating current is supplied to the pair of electromagnets to demagnetize the pair of electromagnets before the measurement step. This is a measurement method.

According to the magnetic characteristic measuring method according to the fourth aspect of the present invention, the residual magnetic flux density of the core in the pair of electromagnets is determined by supplying a attenuated alternating current to the pair of electromagnets and demagnetizing them before the measuring step. The influence can be reduced, and the reliability of the measurement result for a soft material (soft magnetic material) or a semi-hard material (semi-hard magnetic material) can be improved.

According to the present invention, it is possible to provide a magnetic characteristic measuring device and a magnetic characteristic measuring method capable of appropriately evaluating magnetic characteristics even when the core spacing of electromagnets is different.

It is an overall block diagram of the magnetic characteristic measuring apparatus which concerns on this invention. It is a graph which shows an example of the electromagnet characteristic information which concerns on this invention partially. It is a flowchart which shows the control procedure which a measurement control part executes in magnetic characteristic measurement. It is a figure which shows typically the waveform of the exciting magnetic field, the exciting current, and the magnetic hysteresis loop of the magnetic characteristic measuring apparatus which concerns on this invention. It is a figure which shows typically the waveform of the exciting magnetic field and the magnetic hysteresis loop which concerns on the magnetic characteristic measurement method of the prior art. This is an example of the waveform of the attenuated alternating current applied to the core. It is a graph which shows typically the influence of the residual magnetic field about the magnetic flux density generated by a pair of electromagnets.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described below, and can be arbitrarily modified and implemented without changing the gist thereof. In addition, the drawings used for explaining the embodiments are all schematically showing the constituent members, and are partially emphasized, enlarged, reduced, or omitted in order to deepen the understanding of the constituent members. It may not accurately represent the scale or shape.

FIG. 1 is an overall configuration diagram of the magnetic characteristic measuring device 1 according to the present invention. The magnetic property measuring device 1 is a system for measuring the magnetic hysteresis loop of the magnetic material 2 by measuring the magnetic flux density of the magnetic material 2 when a magnetic field is applied. In the present embodiment, the magnetizing device 10 is used. , BH analyzer 20, and control device 30.

Here, the magnetic material 2 is a measurement target whose magnetic characteristics are unknown, and will be described as being composed of, for example, a hard material (hard magnetic material), but a soft material (soft magnetic material) or a semi-hard material (semi-hard magnetic material). It may be. The magnetic material 2 is formed in a columnar shape having a known cross-sectional area.

The magnetization device 10 has a handle for manually adjusting the separation interval G between the pair of electromagnets 11 arranged so as to sandwich the magnetic material 2, the yoke 12 forming a closed magnetic path in the pair of electromagnets 11, and the pair of electromagnets 11. 13 is provided. The pair of electromagnets 11 include a core 11a and a solenoid coil 11b, respectively, and an exciting magnetic field is generated and magnetized with respect to the magnetic material 2 by supplying an exciting current to the solenoid coil 11b wound around the core 11a. be able to. The waveform shapes of the exciting current and the exciting magnetic field are triangular waves and sine waves with relatively low frequencies that can be regarded as direct current.

In the pair of electromagnets 11 in the present embodiment, the separation interval G is manually set according to the dimensions of the magnetic material 2, and the measurer reads the separation interval G. However, the separation interval G is set and read. May be configured to be done automatically.

The BH analyzer 20 is a device that measures the magnetic characteristics of the magnetic material 2 by measuring the magnetic flux density B of the magnetized magnetic material 2 while controlling the magnetization device 10, and is a device that measures the magnetic characteristics of the magnetic material 2, the search coil 21, the hall sensor 22, and H. The measurement unit 23, the B measurement unit 24, and the power supply unit 25 are included.

The search coil 21 is a coil wound around the magnetic material 2 and measures the voltage induced as the magnetic material 2 is magnetized. Further, the Hall sensor 22 as the "magnetic field sensor" measures the voltage associated with the magnetic field strength generated between the pair of electromagnets 11.

The H measuring unit 23 calculates the magnetic field strength H generated between the pair of electromagnets 11 based on the voltage acquired from the Hall sensor 22. Further, the B measurement unit 24 calculates the magnetic flux density B associated with the magnetization of the magnetic material 2 based on the voltage acquired from the search coil 21. Then, the power supply unit 25 supplies an exciting current having a current waveform, which will be described later, to the solenoid coil 11b of the pair of electromagnets 11.

The control device 30 includes, for example, a computer such as a known personal computer, and includes an input unit 31, an output unit 32, a measurement control unit 33, and a storage unit 34. The control device 30 comprehensively manages the measurement of the magnetic characteristics of the magnetic material 2 by exchanging control signals and measurement data with and from the BH analyzer 20 via the communication cable C. The BH analyzer 20 and the control device 30 may be integrally configured.

The input unit 31 is an input interface including, for example, a keyboard, a mouse, a numeric keypad, and the like, and as will be described in detail later, inputs the amplitude and period of the exciting magnetic field for exciting the magnetic material and the separation interval G between the pair of electromagnets 11. Used for. Further, the output unit 32 is an output interface including, for example, a display for displaying measurement conditions and measurement results, and when an operation related to magnetic characteristic measurement is executed on an application, an operation button or the like related to the measurement operation is displayed. To. The output unit 32 may store the measurement conditions and the measurement information of the measurement results in the storage unit 34 by outputting the measurement information to the storage unit 34 described later, or transmit the measurement information to an external device. May be good.

The measurement control unit 33 executes the measurement control of the magnetic characteristics of the magnetic material 2 according to the control procedure related to the magnetic characteristics measurement method, as will be described in detail later.

The storage unit 34 stores the electromagnet characteristic information obtained in advance for each distance G of the pair of electromagnets 11 with respect to the magnitude of the magnetic field strength with respect to the magnitude of the exciting current of the pair of electromagnets 11. Then, when performing the magnetic characteristic measurement, the measurement control unit 33 sets the measurement condition of the magnetic characteristic by reading out the necessary information from the electromagnet characteristic information stored in the storage unit 34.

FIG. 2 is a graph partially showing an example of electromagnet characteristic information according to the present invention. More specifically, FIG. 2 shows the magnitude of the current I supplied to the solenoid coil 11b and the Hall sensor 22 for the pair of electromagnets 11 described above when the separation intervals G are 10 mm, 20 mm, and 30 mm, respectively. It is the measurement data of the IB characteristic which shows the relationship with the magnitude of the magnetic flux density B. When the magnetic permeability of the core 11a is μ, the magnetic flux density B can be converted into the magnetic field strength H through the known relationship of B = μH.

The IB characteristics shown in FIG. 2 are measured in advance for a plurality of separation intervals G in a state where the magnetic material 2 is not arranged in the magnetization device 10 described above. Further, based on the plurality of the measurement data, the IB characteristic can be calculated even for the unmeasured separation interval G by estimation by correlation or interpolation processing, and the separation interval within the expected range can be calculated. A correspondence table (data table) between the current I and the magnetic flux density B with respect to G is prepared as electromagnet characteristic information, and is stored in the storage unit 34 in advance.

Next, the control procedure related to the magnetic characteristic measurement method will be described. FIG. 3 is a flowchart showing a control procedure executed by the measurement control unit 33 in the magnetic characteristic measurement. The measurement control unit 33 executes the control procedure shown in FIG. 3 in a state where the magnetic material 2 around which the search coil 21 is wound is arranged so as to be sandwiched between the pair of electromagnets 11 (arrangement step), thereby performing the magnetic material. Measure the magnetic characteristics of 2.

After the preparation by the arrangement step is completed, the measurement control unit 33 in the control device 30 starts the control procedure shown in FIG. 3 and determines whether or not the necessary setting information is input by the input unit 31. More specifically, the measurement control unit 33 determines whether or not the set values of the amplitude and period of the exciting magnetic field for exciting the magnetic material 2 and the separation interval G of the pair of electromagnets 11 are input (step). S1, set value acquisition process).

When it is determined that the necessary setting information has not been input (No in step S1), the measurement control unit 33 inputs the setting information to the measurer by, for example, displaying an error message on the output unit 32. And withhold the start of the measurement.

When it is determined that the necessary setting information has been input (Yes in step S1), the measurement control unit 33 calculates the maximum value of the current I supplied to the solenoid coil 11b, that is, the target current value of the exciting current. (Step S2). More specifically, the measurement control unit 33 targets a current value corresponding to the separation interval G input from the input unit 31 and the amplitude of the exciting magnetic field based on the electromagnet characteristic information stored in the storage unit 34. Obtained as a current value.

When the target current value is calculated, the measurement control unit 33 sets the current waveform of the exciting current supplied to the pair of electromagnets 11 based on the period of the exciting magnetic field input from the input unit 31 and the target current value. (Step S3). That is, the measurement control unit 33 sets the calculated target current value and the period of the exciting magnetic field input from the input unit 31 as the amplitude and period of the exciting current, respectively, as the current waveform of the triangular wave. As a result, the measurement control unit 33 can set the current waveform of the exciting current supplied to the pair of electromagnets 11 through the procedures of steps S2 and 3.

FIG. 4 is a diagram schematically showing waveforms of an exciting magnetic field, an exciting current, and a magnetic hysteresis loop of the magnetic characteristic measuring apparatus 1 according to the present invention. More specifically, FIG. 4 (a) is a waveform of the excitation magnetic field applied in the magnetizing device 10 in the magnetic material 2, any input from the input unit 31 amplitude (target field H _T) and period P It is a triangular wave defined by. Further, FIG. 4B is a waveform of an exciting current supplied to the solenoid coil 11b in order to apply the exciting magnetic field to the magnetic material 2.

Here, FIG. 4B shows the current waveforms of the respective exciting currents in the case of measuring two magnetic materials 2 made of the same material and having different dimensions. More specifically, the current waveform W1 is in the case the dimensions of the magnetic material 2 is small separation distance G of relatively small pair of electromagnets 11, the amplitude of the excitation current necessary for the application of the target magnetic field H _T is relatively This is the exciting current when the current value I1 is small. In contrast, the current waveform W2, in the case the dimensions of the magnetic material 2 is large separation distance G of relatively large pair of electromagnets 11, a relatively large current as the amplitude of the excitation current necessary for the application of the target magnetic field H _T The exciting current when the value I2 is required.

That is, in steps S3 and S4 of FIG. 3, the current waveform of the exciting current to be supplied to the solenoid coil 11b is set according to the separation interval G of the pair of electromagnets 11 (current waveform setting step).

Then, when the current waveform is set, the measurement control unit 33 starts exciting the pair of electromagnets 11 according to the current waveform, and measures the initial magnetization curve of the magnetic material 2 (step S4). Here, initial magnetization curve of the magnetic material 2 is represented as a curve from the origin O to the magnetic saturation point P _MS in the magnetic hysteresis loop of FIG. 4 (c).

Initial magnetization curve, time to the magnetic field intensity applied to the magnetic material 2 reaches the target magnetic field H _T, i.e. in the period up to the time t _MS corresponding to a quarter of the period P of the excitation magnetic field and the excitation current as described above It is measured based on the magnetic flux density B detected by the search coil 21. Therefore, the measurement control unit 33 _{determines whether or not the time t MS for the} magnetic material 2 to reach magnetic saturation has elapsed (step S5), and continues the measurement of the initial magnetization curve until the _{time t MS elapses (step S5).} No in S5).

When the time t _MS from the start of measurement has elapsed (Yes in step S5), and the measurement control unit 33, or the magnitude of the magnetic field intensity H to be measured by the Hall sensor 22 has reached the above predetermined magnetic field threshold H _TH It is determined whether or not (step S6). Here, the magnetic field threshold value H _TH is a threshold value arbitrarily set in advance for determining whether or not a sufficient magnetic field strength is applied to the magnetic material 2, and is slightly larger than _{, for example, the target magnetic field H T.} Set as a low value.

Then, when the magnetic field strength H is _{less than the magnetic field threshold value H TH} (No in step S6), the measurement control unit 33 displays an error via, for example, the output unit 32 (step S7), so that the desired magnetic field Notify the measurer that the intensity H cannot be obtained, and end the magnetic characteristic measurement. Here, the state in which the magnetic field strength H is _{less than the magnetic field threshold value HTH} is when the exciting current applied to the pair of electromagnets 11 is insufficient, or when the measurer forgets to install the Hall sensor 22. is assumed.

On the other hand, when the magnetic field strength H _{is equal to or higher than the magnetic field threshold value H TH} (Yes in step S6), the measurement control unit 33 assumes that the measurement of the initial magnetization curve has been completed normally, and magnetically measures according to the set current waveform. The hysteresis loop of the magnetic material 2 is measured by continuing the above (step S8). As a result, as shown in FIG. 4C, the major loop of the magnetic material 2 is measured.

Here, in the magnetic characteristic measuring device 1 according to the present invention, since the waveform shape of the exciting current is set based on the electromagnet characteristic information acquired in advance, it is applied to the magnetic material 2 regardless of the dimensions of the magnetic material 2. The period and amplitude of the exciting magnetic field to be generated are standardized. Therefore, according to the magnetic property measuring apparatus 1 according to the present invention, even if there are a plurality of magnetic materials 2 having different dimensions, as long as the magnetic materials 2 are made of the same material, they are shown in FIG. 4 (c). As described above, the magnetic characteristics can be fairly evaluated as the same hysteresis loop.

Subsequently, as a comparison target with respect to the present invention described above, the magnetic property measurement according to the prior art will be described. FIG. 5 is a diagram schematically showing waveforms of an exciting magnetic field and a magnetic hysteresis loop according to a conventional method for measuring magnetic characteristics. The In the prior art, to increase the exciting current applied to the pair of electromagnets 11 at a predetermined pace, the period of the excitation magnetic field based on the time the magnetic field strength H which is measured by the Hall sensor 22 has reached the target magnetic field H _T It is set.

Here, in the case where the magnetic characteristics of two magnetic materials 2 made of the same material but having different dimensions are measured by the prior art, the magnetic field waveforms of the respective exciting magnetic fields are set as the magnetic field waveform W3 and the magnetic field waveform W4 in FIG. 5A. Shown. More specifically, the magnetic field waveform W3, in case the size of the magnetic material 2 is smaller separation distance G of relatively small pair of electromagnets 11, a relatively short excitation field time t1 to reach the target magnetic field H _T is Is. In contrast, the magnetic field waveform W4, in the case the dimensions of the magnetic material 2 is relatively large separation distance G of the pair of electromagnets 11 is large, by the excitation magnetic field takes a relatively long time t2 to reach the target magnetic field H _T is there.

That is, in the magnetic characteristic measuring method according to the prior art, since the period of the excitation magnetic field relative to the magnetic field intensity H to be measured by the Hall sensor 22 is set, although capable of exciting the magnetic material 2 in reliably target magnetic field H _T, The period of the exciting magnetic field changes depending on the separation interval G of the pair of electromagnets 11. In this case, the width (range of magnetic field strength) of the measured magnetic hysteresis loop is overestimated as the period of the exciting magnetic field is shorter as shown by the solid line in FIG. 5 (b). As shown, the longer the period of the exciting magnetic field, the underestimated the width. That is, even if two magnetic materials 2 made of the same material are measured, it becomes impossible to appropriately evaluate the magnetic characteristics due to the difference in dimensions. In FIG. 5B, the drawing of the initial magnetization curve is omitted.

As described above, in the magnetic characteristic measuring device 1 according to the present invention, the relationship between the exciting current and the magnetic field strength for each separation interval G of the pair of electromagnets 11 is stored in advance, and the magnetic material to be measured is excited. By inputting the amplitude and period of the exciting magnetic field of, the current waveform of the exciting current applied to the pair of electromagnets 11 is set. At this time, the current waveform of the exciting current can be regardless of the magnitude of the separation distance G, which has an amplitude required to apply the target magnetic field H _T in the magnetic material 2, to set the period arbitrarily. Therefore, for example, even when two magnetic materials 2 made of the same material and having different dimensions are measured, the magnetic characteristics can be fairly evaluated under the same conditions by unifying the period of the exciting current. .. Therefore, according to the magnetic characteristic measuring device 1 according to the present invention, it is possible to appropriately evaluate the magnetic characteristics even when the core spacing of the electromagnets is different.

<Modification example>
When the magnetic characteristics of a hard material (hard magnetic material) are measured by a relatively large exciting magnetic field in the magnetic characteristics measuring device 1 according to the present invention described above, the magnetic field associated with the coercive force of the core 11a in the pair of electromagnets 11 Is likely to remain. In this state, for example, when the magnetic characteristics of a soft material (soft magnetic material) or a semi-hard material (semi-hard magnetic material) are continuously measured, the exciting magnetic field to be applied is excited even though the range is relatively narrow. Since the initial value of the magnetic field is not 0, the reliability of the measurement result is lowered.

Therefore, in the above-mentioned magnetic property measuring device 1, the power supply unit 25 supplies a damped alternating current to the pair of electromagnets 11 based on the control from the control device 30 before the measuring step of measuring the magnetic property of the magnetic material 2. As a result, the cores 11a of the pair of electromagnets 11 are configured to be demagnetized. FIG. 6 is an example of the waveform of the attenuated alternating current applied to the core 11a. At this time, the pair of electromagnets 11 having a relatively large inductance are efficiently demagnetized by a relatively low frequency attenuated alternating current corresponding to the magnitude of the inductance.

FIG. 7 is a graph schematically showing the influence of the residual magnetic field on the magnetic flux density generated by the pair of electromagnets 11. More specifically, FIG. 7 is a graph of IB characteristics showing the relationship between the magnitude of the current I supplied to the solenoid coil 11b and the magnitude of the magnetic flux density B generated by the pair of electromagnets 11.

When the core 11a of the pair of electromagnets 11 is demagnetized by the demagnetization function according to the present invention, the current I supplied to the solenoid coil 11b is 0 [A] as shown by the characteristic α in FIG. In this case, the magnetic flux density B becomes 0 [T]. Therefore, even when the current I supplied to the solenoid coil 11b is relatively small in the measurement of the magnetic characteristics of a soft material (soft magnetic material) or a semi-hard material (semi-hard magnetic material) having a relatively small range of exciting magnetic fields. The magnetic material 2 can be excited with the magnetic flux density B corresponding to the current I, and the reliability of the measurement result can be improved.

On the other hand, when the cores 11a of the pair of electromagnets 11 are not demagnetized, as shown by the characteristic β in FIG. 7, the magnetic material is made even if the current I supplied to the solenoid coil 11b is 0 [A]. The residual magnetic flux density _BR [T] is applied to 2. Along with this, the value of the magnetic flux density B in the range where the current I supplied to the solenoid coil 11b is relatively small becomes inaccurate, and the reliability of the measurement result is lowered.

As described above, according to the magnetic characteristic measuring device 1 according to the modified example of the present invention, before the measuring step, a decaying alternating current is supplied to the pair of electromagnets 11 to demagnetize the pair of electromagnets 11. it is possible to reduce the effect of residual magnetic flux density B _R of the core 11a in the magnetic property measurement, is possible to especially improve the reliability of the measurement results for the soft material (soft magnetic material) and semi-hard material (semi-hard magnetic material) it can.

1 Magnetic property measuring device 2 Magnetic material 10 Magnetizing device 11 Pair of electromagnets 11a Core 11b Solenoid coil 20 BH analyzer 21 Search coil 22 Hall sensor 30 Control device 31 Input unit 33 Measurement control unit 34 Storage unit

Claims (4)

A pair of electromagnets around which the search coil is wound and arranged so as to sandwich the magnetic material,
A magnetic field sensor that measures the magnetic field strength between the pair of electromagnets,
A control device for measuring the magnetic characteristics of the magnetic material by the magnetic field strength measured by the magnetic field sensor and the magnetic flux density measured by the search coil while supplying an exciting current to the pair of electromagnets is provided.
The control device includes a storage unit that stores the relationship between the exciting current and the magnetic field strength acquired in advance for each distance between the pair of electromagnets as electromagnet characteristic information, and the amplitude and period of the exciting magnetic field that excites the magnetic material. Includes an input unit into which is input and a measurement control unit that executes measurement control of the magnetic characteristics.
The measurement control unit acquires a target current value corresponding to the separation interval and the amplitude of the exciting magnetic field based on the electromagnet characteristic information, and the period of the exciting magnetic field input from the input unit and the target. A magnetic characteristic measuring device that sets a current waveform of the exciting current based on a current value. The magnetic characteristic measuring device according to claim 1, wherein the measurement control unit supplies a attenuated alternating current to the pair of electromagnets to demagnetize the pair of electromagnets before measuring the magnetic characteristics. An arrangement process in which the magnetic material around which the search coil is wound is arranged so as to be sandwiched between a pair of electromagnets, and
A set value acquisition step for acquiring the set values of the amplitude and period of the exciting magnetic field for exciting the magnetic material and the separation interval of the pair of electromagnets.
A current waveform setting step for setting the current waveform of the exciting current supplied to the pair of electromagnets, and
A measurement step of acquiring the magnetic field strength between the pair of electromagnets when excited by the current waveform and the magnetic flux density measured by the search coil to measure the magnetic properties of the magnetic material is included.
In the current waveform setting step, the separation interval and the amplitude of the exciting magnetic field are obtained based on the electromagnet characteristic information as the relationship between the exciting current and the magnetic field strength acquired in advance for each separation interval of the pair of electromagnets. A method for measuring magnetic characteristics, in which a target current value corresponding to is acquired, and the current waveform is set from the period of the exciting magnetic field and the target current value. The magnetic characteristic measuring method according to claim 3, wherein a attenuated alternating current is supplied to the pair of electromagnets to demagnetize the pair of electromagnets before the measuring step.

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